Partitioning 3D Surface Meshes Using Watershed Segmentation

320 IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS, VOL. 5, NO. 4, OCTOBER-DECEMBER 1999
Fig. 17. Several subassemblies of the dart model isolated via region extraction.
single vertex. In this manner, the region boundaries (edges)
are preserved.
Another area that can benefit from the use of the
segmentation method proposed here is that of computeraided
design. It is possible to read in a general mesh model
without any knowledge of its structure save its basic
connectivity and segment it and extract any desired regions
using the user-specified threshold. Subparts can then be
analyzed in detail and the model modified by modifying or
deleting assemblies as required. These parts and assemblies
can then be added to a database of such parts and
recombined and reused in different configurations as
needed. A surface mesh can be created using an interactive
3D model generation tool and measurements and specifications
for various subassemblies then generated from the
segmented model. Fig. 17 shows several parts of the dart
extracted from the model as a whole.
6 CONCLUSIONS
We have presented here a method of surface segmentation
which uses a generalization of watershed regions to 3D
meshes. The method can segment either isosurfaces of a 3D
volume or surface meshes directly into regions that are
bounded by higher curvature. The algorithm displays some
sensitivity to the user-specified threshold. Varying the
threshold allows for different levels of segmentation, the
exact level depending upon the final application.
One aspect of the system that would benefit from future
work is the method of calculating curvature for surface
meshes. Currently, the results obtained from segmentation
of these meshes are prone to high frequency aliasing and
Fig. 18. Mesh reduction on unsegmented and segmented surface. (a) Reduction by a factor of 100 on the unsegmented dart, (b) the vertex
connectivity of the unsegmented reduction, (c) reduction by a factor of 100 on the segmented dart, (d) the vertex connectivity of the segmented
reduction.